A semiconductor manufacturing process includes a photolithography process comprising applying a photoresist (hereinafter simply referred to as a resist) to a surface of a semiconductor wafer (hereinafter simply referred to as a wafer), exposing the resist in a predetermined pattern, and developing the exposed resist to form a resist pattern. A coating and developing apparatus for forming such a resist pattern includes a processing block having processing modules for performing various types of processing of a wafer.
The processing block is comprised of a stack of unit blocks for forming various types of coating films (e.g. resist film) and unit blocks for performing developing processing, as described e.g. in Japanese Patent Laid-Open Publication No. 2007-115831 (JP2007115831A). Each unit block has therein a wafer transport mechanism, by which a wafer is transported to various processing modules provided in each unit block, in which the wafer undergoes processing in the processing modules according to a predetermined order.
In order to meet recent demands for finer resist patterns, processing modules provided in a processing block are becoming diversified. For example, besides a resist film-forming module for applying a resist onto a wafer and a developing module for supplying a developer to the wafer, a processing block may also be provide with a hardening liquid supplying module for hardening a patterned resist film to allow repetitive photolithography process, and an upper protective film-forming module for forming a protective film for immersion exposure. With an increased number of diverse processing modules provided in a processing block of a coating and developing apparatus, there is a problem of how to reduce the increase in the footprint of the apparatus.
In the coating and developing apparatus disclosed in JP2007-115831A, the wafers are transported sequentially among the modules in the unit blocks. Thus, if one of the processing modules fails, the wafers can no longer be transported to the processing module for the later-stage processing. This significantly may lower the operation efficiency of the apparatus.